The show will continue to follow the lives of Janelle Evans, Leah Messer and Kailyn Lowry, who are all 19, and Chelsea Houska, who is 20.

Viewers ended last season watching Lowry become involved in a bitter war of words with her ex, Jonathan "Jo" Rivera, over custody of their son, 22-month-old Isaac.

"Right now we're in a good place and we're still trying to co-parent," Lowry told "Good Morning America," of where the couple stands today. "We're still on a rollercoaster, but right now we're in a good place."

While Lowry fought with her ex in season one, Houska tried in vain to make a life with her on-again-off-again boyfriend, Adam Lindt, the father of her 2-year-old daughter, Aubree.

"I always wanted my family together. I believe children should have a full family," Houska said today on "GMA." "You should be married when you have a child."

"When you have a kid young, you just can't always give them that opportunity," she said.

"Teen pregnancy and teen birth has declined dramatically since the early '90s," Amy Kramer, director of entertainment media and audience strategy at the National Campaign to Prevent Teen and Unplanned Pregnancy, told "GMA."

"There are shows like this showing teenagers how hard it really is," Kramer said. "It's letting them understand for themselves and make better decisions in their lives."

While "Teen Mom" has become a bona fide hit for MTV, and earned its stars six-figure incomes and their faces on the cover of tabloid magazines, it has also put a spotlight on their controversial behavior, on and off camera.

One "Teen Mom" star, Amber Portwood, reportedly attempted suicide earlier this year after fighting with her ex, Gary Shirley. Portwood had previously pleaded guilty to a domestic violence charge, after slapping and punching Shirley, and lost custody of their 2-year-old daughter, Leah.

And Lowry and Houska's fellow "Teen Mom 2" star, Janelle Evans, was arrested in March after video surfaced of her punching a former friend in her Oak Branch, N.C., hometown. Evans was eventually charged with simple assault and simple affray. She's also been busted on drug possession charges.

"It [the show] can add a certain level of stress because there are certain times where you feel really vulnerable and you want to experience something by yourself but you have these cameras there," Lowry said of her experience.

"But I think part of it is pretty good because we get everything documented, which some people don't really have the opportunity to do" she added.

"We get a look back at mistakes we made and try to improve on them," Houska said. "We try extra hard to be good role models for the other girls out there."

Critics have also said the series encourages teenage girls to become pregnant. Eyebrows were raised when three of Evans' teenage friends had become pregnant. Those developments fueled speculation on the Internet that the teenagers got pregnant for fame's sake, labeling them "copycat moms."

Houska's best friend, Megan Nelson, who made cameo appearances on the first season of "Teen Mom 2," gave birth to a son of her own, Hunter, in July.

"I think if you watch any amount of this show, there's no way you can come away from it and say this is easy and this is glamorous and this is something I want to do in my own life," Kramer said in response to the speculation. "These girls are struggling."

The show's stars too say their lives' as played out on television should do anything but encourage other girls to do the same.